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22 terms

acute angle

An angle that measures less that 90 and more than 0

alternate exterior angles

Two nonadjacent angles on opposite sides of a transversal and outside the lines crossed by the transversal.

alternate interior angles

Two nonadjacent angles on opposite sides of a transversal that are inside the lines crossed by the transversal.

angle bisector

A line or ray that divides an angle in half

base angles

The angles opposite the two equal sides in an isosceles triangles. A pair of angles that share a base as a common side in a trapezoid

complementary angles

Two angles that add up to 90

congruent triangles

Triangles that have the same shape and size

convex polygons

A polygon in which the measure of each angle is less than 180º

corresponding angles

Angles that are located in similar places along a transversal that intersects two lines; also, angles from congruent or similar figures in corresponding positions

exterior angle

An angle formed by one side of a polygon and the extension of an adjacent side

interior angle

The angle that open toward the inside of the polygon

isosceles triangle

A triangle with two sides of equal length

obtuse angle

An angle that measures more than 90 and less than 180

parallel lines

Straight lines in a plane that never intersect, no matter how far they are extended

reflex angle

An angle of measure greater than 180 and less than 360

scaling factor

The ratio of the lengths of corresponding sides of two similar figures

similar

Two objects such that the distance between any two points of one object is a particular constant times the distance between the corresponding points of the other object

straight angle

An angle that measures 180

supplementary angles

Two angles that add up to 180

transversal

A straight line that intersects two or more other coplanar straight lines at distinct points

vertical angles

Congruent angles that form opposite each other when two lines intersect

co-interior angles

Two nonadjacent angles on same sides of a transversal that are inside the lines crossed by the transversal